It is often desirable to obtain a sample of fluid which is held in a container or the like. Fluid samples are usually subjected to tests to determine the contents of the sample. Particularly in the field of work vehicles, fluid samples are taken at regular intervals because the sampling process is generally less expensive than changing the fluid. Many types of fluid, such as hydraulic fluid, engine oil, and transmission fluid, are commonly sampled so that the fluid may be tested for contaminates which result from vehicle operation and the operating environment. When the contaminates reach an undesirable level, the contaminated fluid is changed. Moreover, contaminates in fluid samples may also give an early indication of a component wear or failure. Therefore, the samples alert service personnel so that major failures or unexpected downtime are avoided.
Since some samples contain potentially hazardous constituents, it is advantageous to use a fluid sampling device which minimizes the risk of spilling the fluid sample on the sampling personnel or the surrounding area. Sampling devices have progressed so that they are partially or fully sealed to reduce spillage. Preferably, the material of the sampling device is inert with respect to the fluid and relatively unbreakable. Sampling devices should also be easy to use, inexpensive to manufacture, and adaptable to containers and openings of various designs.
Previous sampling devices have attempted to embody the above-mentioned attributes with varying degrees of success. U.S. Pat. No. 4,580,454, issued Apr. 8, 1986 to Deja, discloses a sampling tube, one end of which is inserted into a fluid so that a fluid sample enters the tube by displacing a portion of the air in the tube. A rod, having a handle on one end and a stopper on the other end, extends the length of the tube. When the handle is pulled upwardly, the stopper moves into contact with the bottom of the tube to retain the fluid sample within the tube. The handle is then pivoted into a locking position to prevent the stopper from dislodging from the end of the tube. A valve within the tube seals an upper portion of the tube when the stopper seals the bottom of the tube. One drawback of this device is that it needs to be manufactured to strict tolerances to insure proper operation for the valves as they are moved and locked by the handle. Moreover, there is no provision for adapting the device to sample fluid from a container which is deeper than the length of the tube or which has an opening smaller than the diameter of the tube.
In addition, sampling devices have not heretofore been available in which a suitable material is utilized such that the sampler is chemically resistant to the samples, inexpensive, relatively unbreakable and allows for visual inspection through the sampling device. For example, the use of glass samplers involves a risk that the sampler will break as the sample is obtained. Other materials such as PVC, polycarbonate, and polystyrene and polyolefins are adversely affected by many chemicals and/or do not provide sufficient visibility of the sample.
A lingering, unsolved problem with Coliwasa samplers is primarily a material problem, for a truly suitable material for forming a sampler has previously not been found. Coliwasas are used to sample hazardous waste material where one encounters the need to sample acids, caustics, aromatic hydrocarbons, aliphatic hydrocarbons, chlorinated hydrocarbons, ketones, alcohols, esters, etc. A sampler for the full variety of chemical substances known to man, must as top priority, be sufficiently chemically resistant to ensure the personal safety of those sampling the hazardous chemical. It must similarly be breakage-resistant and transparent enough to permit visual evaluation of the sample obtained.
Heretofore only two materials for sampler construction have been found which are suitable for nearly or all the chemicals likely to be encountered; Teflon and glass. However, glass breaks, and Teflon is both expensive and opaque. Samplers constructed of metal are attacked by acids and caustics and are non-see through; samplers of PVC are attacked by organic materials and petroleum products. Polycarbonate, polystyrene, ABS, cellulose acetate butyrate, nylon, etc. are all effected substantially by many chemicals.
Polyolefins (high density polyethylene and polypropylene) are generally cost-competitive and have good chemical resistance. The disadvantage of polyolefins is that they are translucent, not transparent. The functional requirement that the sample be visibly inspected right after sampling was not achievable, and copolymers such as those used to achieve clear polypropylene yield a flexible material--(not rigid). Consequently, polyolefins have been rejected as a suitable material for sampler construction.
In known devices it is often necessary to transfer the sample to a jar or other container for visual inspection or transportation. This makes the process more cumbersome since additional containers must be carried. In addition, clean-up is more time consuming since additional containers must be cleaned. The possibility that the sample will be spilled, or impurities introduced is also increased where it is necessary to transfer the sample into a separate container.
Suitable stoppers which are both pliable and chemically resistant have also been unavailable. For example, neoprene has been found unsuitable as a stopper material since it is not resistant to ketone, chlorinated solvents. Rubber and silicone are also unacceptable since although pliable, they are not chemically resistant to certain solvents. Although polytetrafluoroethylene (marketed by DuPont under the trademark Teflon) exhibits suitable chemical resistance, it is not pliable enough to ensure a reliable seal.
The present invention is directed to overcoming one or more of the problems as set forth above.